The present invention relates generally to an inflation/deflation device for a balloon catheter used in the treatment of vascular obstructive lesions and particularly relates to an inflation/deflation device for percutaneous transluminal balloon valvuloplasty.
Catheter techniques for percutaneous transluminal treatment of vascular obstructive lesions have been used in the past. Balloon angioplasty of the peripheral vessels was subsequently introduced and extended to treatment of coronary artery obstructions. This technique was subsequently further extended to treatment of certain congenital heart lesions, including pulmonary valve stenosis, coarctation of the aorta, peripheral pulmonary artery stenosis, aortic stenosis and other stenotic or obstructive lesions.
Generally, in percutaneous transluminal balloon valvuloplasty, a balloon catheter is introduced over a guidewire into the area of the valvular obstruction. More specifically, by using radio-opaque markers indicative of the proximal and distal limits of the balloon, the balloon may be located substantially medially of the valve. The balloon is then inflated, usually with a dilute contrast medium, for a predetermined period of time to apply a controlled radial force to the balloon to open the valve, i.e., rupture the obstructive lesion about the valve. The balloon is then deflated. The process of inflation and deflation is repeated several times.
In the course of inflating the balloon catheter with the fluid, substantial pressures are necessary to open or rupture the obstructive material about the valve. For example, pressures on the order of 80-120 psi and higher may be necessary to effect opening of the valve. In conventional balloon valvuloplasty, the proximal end of the catheter is coupled to a syringe containing the inflating fluid. In most instances, the syringe is manually manipulated to inflate and deflate the balloon. However, it has been found to be physically difficult and exhausting to inflate the balloon to the desired pressure, to maintain that pressure over a predetermined period of time, and repeat that procedure several times. Substantial physical strength is required and not all individuals have the required strength to perform this function.
This problem has been addressed in U.S. Pat. No. 4,655,749. However, the device of that patent uses a drive screw fixed to a piston to effect displacement of the plunger of the syringe. Rapid inflation and deflation, therefore, cannot be effected with this device. In essence, that device simply substituted a screw drive for the conventional manual push/pull action on the plunger of a syringe, with little regard to the guick manipulation required necessary to effect rapid inflation and deflation of the balloon.
According to the present invention, there is provided a novel and improved inflation/deflation device for a balloon catheter which affords sufficient mechanical advantage or leverage to enable rapid and manual inflation and deflation of the balloon. To accomplish this, the balloon catheter is attached to a syringe in a conventional manner by using extension tubing, the syringe previously being filled with dilute contrast fluid. The syringe is then placed in the inflation/deflation device of the present invention. Particularly, that device includes a pair of elongated members or levers, one of which has an angled end portion extending toward the other member for pivotal connection therewith. The first member with the angled end portion has a central linear portion in which there is provided a recess opening laterally through one side of the member in the direction of the pivotal axis. The recess is further defined by a slot, similarly opening laterally to the same side of the device, for receiving the flange formed on the open end of the barrel of the syringe which receives the plunger. The second member is substantially linear throughout its full length and has a central slot for mounting an extension of a fitting. The fitting lies between the members and has a slot which opens laterally to the same side of the device as the slot of the first member. With this arrangement, the device as the slot of the first member. The syringe may be placed in the inflation device by engaging the conventional flanges of the syringe barrel and its plunger in the respective slots of the first and second members.
End portions of the first and second members opposite their pivotal connection one to the other constitute handles, whereby the members may be pivoted toward and away from one another. It will be appreciated that such pivoting action causes the plunger to be axially displaced into and withdrawn from the barrel. With the location of the syringe intermediate the opposite ends of the first and second members, and recognizing that the handles by which the members are moved toward and away from one another are located at the end of the device opposite the pivotal connection, substantial leverage or mechanical advantage is obtained. This leverage has a force multiplying effect, enabling the rapid pivoting of the members toward one another to inflate the balloon to the required pressure with substantially much less force than required when the plunger of the syringe is directly manually operated. Likewise, substantial leverage is obtained when moving the members away from one another to suction the syringe to rapidly deflate the balloon. Thus, the strength required for manual operation of the inflation/deflation device is minimized because of this lever-type action. Also, this arrangement enables rapid inflation and deflation of the balloon, minimizes the effect of any variability introduced by the strength of individual operators, and also decreases the time required for the procedure, thus increasing the safety of the procedure for the patient.
It is another feature of the present invention that the inflation/deflation device has a limit or stop which permits the members to be pivoted away from one another only to a predetermined extent. That extent is less than necessary to completely withdraw the plunger of the syringe from the syringe barrel. Thus, the plunger may not be inadvertently pulled out of the barrel of the syringe. The limit or stop is adjustable to accommodate different sizes of syringes.
Accordingly, it is a primary object of the present invention to provide a novel and improved inflation/deflation device for a balloon catheter particularly useful for percutaneous transluminal balloon angioplasty or valvuloplasty which minimizes or eliminates the need for substantial strength in operating the device, yet enables an individual operating the device to obtain and maintain the high balloon pressures necessary to open the obstructed site.
It is another object of the present invention to provided a novel and improved inflation/deflation device for a balloon catheter which enables rapid inflation and deflation of the balloon, and minimizes the time required for the procedure, while enhancing the safety of the procedure.
According to a preferred embodiment of the invention, there is provided a inflation/deflation device for a catheter having an inflatable balloon at its distal end and a syringe at its proximal end, the syringe including a cylindrical barrel with an open end and a plunger received within the barrel through its open end, comprising first and second elonated members connected one to the other adjacent corresponding end portions thereof for pivotal movement toward and away from one another about an axis. Means are carried by the first and second members for mounting the barrel and the plunger of the syringe, respectively, at a location spaced from the pivotal connection, the members being pivotal toward and away from one another about the axis to displace the plunger axially relative to the barrel to thereby inflate and deflate the balloon. Preferably, both the barrel mounting means and the plunger mounting means include means defining recesses opening to one side of the members, generally in the direction of the axis of the pivotal connection, for receiving the flanges of the barrel and plunger, respectively, thereby facilitating ready mounting of the syringe to the inflation/deflation device.
The invention consists in the novel parts, constructions, arrangements, combinations and improvements shown and described. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one embodiment of the invention and, together with the description, serve to explain the principles of the invention.